1. Field of the Invention
The present invention relates to a fuel supply control system for an internal combustion engine, and more particularly, to such a fuel supply control system which is adapted to electrically control the amount of fuel to be supplied to an engine in an electrical way on the basis of data which is previously stored in a memory for determining the optimal amounts of fuel for respective engine operating conditions determined by manifold pressure and RPM of the engine, and which is read out in response to the ever-changing engine operating conditions.
2. Description of the Prior Art
Various kinds of fuel supply control systems for internal combustion engines have hitherto been proposed which control, by detecting the amount of intake air sucked into an engine as desired from manifold pressure and RPM of the engine, the amount of fuel to be supplied to the engine by means of a fuel injection valve, which is operated to open and close in synchronization with RPMs so as to maintain the air/fuel ratio at a predetermined value.
In recent years, many internal combustion engines have an exhaust gas recirculation system (hereinafter referred to as EGR) in order to cope with automotive emission controls imposed by governments of various countries. In such cases, with the above-described conventional fuel supply control systems in which the amount of intake air is detected from the manifold pressure and RPM's, it is impossible to precisely control the amount of fuel being supplied to an engine in such a manner as to provide a predetermined air/fuel ratio. That is, in cases where EGR control is effected, the pressure detected as manifold pressure also includes the pressure of the EGR gas which does not contribute to the combustion of fuel, thereby making it impossible to detect the actual amount of intake air in a precise manner. As a result, it is difficult to precisely control the amount of fuel to be supplied to the engine to provide a predetermined air/fuel ratio.